Cigarette filter element



June 23, 1970 KALsEY 3,516,419

CIGARETTE F ILTER ELEMENT Filed Feb. 27, 1969 l8 0 l4 :8 B

INVENTOR. JOHN KALSEY ATTORNEYS United States Patent 3,516,419 CIGARETTE FILTER ELEMENT John Kalsey, 402 Laurel Ave., Menlo Park, Calif. 94025 Continuation-impart of abandoned application Ser. No. 632,654, Apr. 21, 1967. This application Feb. 27, 1969, Ser. No. 805,992

Int. Cl. A24d 1/04, 1/06; A24f 7/04 .5. Cl. 131-267 4 Claims ABSTRACT OF THE DISCLOSURE A smoke filter element comprising yarn helically wound about a central longitudinal axis centrally of the filter element. A first yarn winding or central core is formed or provided to which successive helically wound layers of yarn are wound circumferentially thereabout. These successive windings are coextensive in length with the first winding or core and are adjoined longitudinally along all segments of their respective helical winds by adjacent yarn also helically wound. This winding provides a firm and porous filter mass capable of absorbing substantial portions of tars, nicotines and other compounds produced by the combustion of tobacco. The disclosed filtered element can be saturated with a viscous liquid adhesive which is non-toxic, neutral tasting and has the properties of chemical base. The element is provided with a non-porous, encircling boundary having openings at either end of the core or first winding thereby confining smoke interior of the element to a circumfiuous interpenetrating path traversing the saturated fibers of the helically wound yarn with a minimum of resistance and a maximum of filtration. The fibrous filter mass preferably is impregnated with an adhesive material which comprises cows milk and which manifests the properties of a base neutralizing acid impurities in the smoke.

This application is a continuation-in-part application of the copending patent application Ser. No. 632,654, filed Apr. 21, 1967, now abandoned and entitled Cigarette Filter Element.

This invention relates to a smoke filter element and more specifically to a cigarette filter which has the capability of removing relatively large proportions of tars, nicotines and other compounds produced by the combustion of tobacco.

The filter element of this invention comprises successive layers of yarn helically wound about a central axis. A first winding or central core running the longitudinal length of the filter element provides the foundation for successive layers of helical windings wound circumferentially thereto. These successive windings are longitudinally coextensive with the central core or first winding and comprise helically wound lengths of yarn, this yarn being longitudinally adjoined along all segments as helically wound by adjacent similarly wound yarn windings. The successive layers of circumferential windings about the central core or first winding and the adjoining relationship of adjacent strands of yarn as helically wound in each of the respective successive layers cooperates to provide an essentially solid and porous filter element through which smoke circumfluously interpenetrates providing maximum filtration with a minimum length of filter and resistance to fluid flow.

Filter elements for smoke have heretofore been constructed from groups of compressed fibers. These fibers, however, have been aligned longitudinally parallel to the central axis of the filter element. This longitudinal alignment of the fibers allows an essentially unrestricted pas- Patented June 23, 1970 sage of the smoke, reducing greatly the filtration effect of such elements.

Accordingly, the present invention aligns the individual fibers traversely with respect to the flow of the smoke thereby forcing this flow of smoke with its contained tars, nicotines and other compounds into a circumfluously interpenetrating path through a fibrous maze. Smoke when restricted to this path is filtered with maximum efiiciency along a minimum length of filter element.

Helical windings have been previously employed in filter elements. These windings, however, have been spacially separated from their adjacent windings leaving interior of the filter element gaps or spaces having the disadvantage of providing an unobstructed air mass through which the smoke may travel essentially unfiltered.

Accordingly, the present invention teaches a helically Wound fibrous filter element which is without such spaces. This end is accomplished by winding successive layers of helically wound yarn about a central longi tudinal axis with each segment of helically wound yarn longitudinally adjoined by adjacent similar windings on both sides thereof. The adjoined strands of the yarn as helically wound produce a porous filter element wholly lacking such objectional spacing.

An object of this invention is to provide an improved fibrous filter mass capable of absorbing substantial portions of tars, nicotines and other compounds produced by the combustion of tobacco. This disclosed filter mass comprises successive layers of helically wound yarn. The yarn is formed from a plurality of individual fiber slivers drawn out and twisted. Centrally of the filter element there is a first winding or central core extending the axial length of the filter element. This core is typically comprised of yarn, but alternately may be any material suitable for providing a foundation for the successive windings of yarn. Yarn is then helically wound immediately about this first winding or central core in successive layers. These layers comprise individual strands of yarn, each strand wound in a helix. At all points along the helix, the yarn is wound so as to adjoin longitudinally on both sides thereof, adjacent strands of similarly wound yarn of the same layer, thus creating a solid but porous filter mass. When the outermost layer of helically wound yarn is surrounded at the periphery or circumference thereof by a cylindrical non-porous boundary having openings at either end of the core, smoke drawn interiorly of the filter will circumfluously interpenetrate the wound fibrous mass achieving optimum filtration with a minimum resistance to fluid flow.

A further object of this invention is to provide a viscous liquid for impregnating the individual fibers of a smoke filter element so as to attain maximum filtration while at the same time adhering the fibrous mass of the element together. Accordingly, the yarn, comprising the helically wound filter element of the present disclosure, is impregnated with a neutral tasting, non-toxic adhesive solution which has chemical properties similar to a base. The filter, when impregnated with such a liquid, adheres in its wound configuration while maintaining interiorly thereof a viscous liquid coating on the individual fibers. This coating, having the properties of a chemical base, interacts with and absorbs, maximum quantities of tars, nicotines and other compounds from passing tobacco smoke.

Other objects and features and advantages of the present invention will be more apparent after referring to the following description and attached drawing in which:

FIG. 1 is a diametric cross section of a cigarette and filter element in accordance with the present invention showing selected windings of the filter element extending above the plane of the cross section; and

FIG. '2 is an elevational view of the filter element of the present invention in the process of being wound.

Referring now to the drawing and with particular reference to FIG. 1, the filter element is shown interior of a tobacco cylinder or cigarette having core A with successive windings B wound thereto and peripherally surrounded by a cylindrical, non-porous filter boundary C.

The yarn 14 which makes up the windings B of the filter element comprises a plurality of twisted, roving strands 18. Strands 18 are in turn formed from a multitude of individual twisted fibers. These fibers are composed of any natural or artificial material which is nontoxic, neutral tasting, and capable of absorbing or adsorbing some impurities along and through the surface thereof.

A particularly advantageous yarn for use with the disclosed filter element comprises individual twisted strands of undyed rayon roving. Fibers of this material when formed into a yarn, have the desired characteristics of swelling or expanding upon impregnation. This swelling decreases the spacing between the individual fibers thereby increasing the filtration effect of the wound fibrous mass.

Rayon has the property of absorbing gases and other ingredients found in tobacco smoke. Moreover, when rayon is lightly impregnated with additives for adhering the strands of roving and improving the filtration properties of the roving, its porosity remains substantially unchanged providing a smooth filter draw.

Core A is shown in FIG. 1 comprising two twisted roving strands 18. This core extends concentrically and axially the length of the filter element and must be of sufficient strength to accommodate the axial loading of successive windings wound peripherally in contact therewith.

As is apparent, core A can alternately be formed from materials other than roving strands 18 which while having no fibers to filter the passing smoke themselves, serve as a foundation for the sequentially wound yarn containing such filter fibers.

Windings B comprise successive layers 20 of yarn 14 wound in helices about the foundation of core A. As is apparent, interior layers 20a has as its immediate foundation core A. Layer 20b wound concentrically about core A has as its immediate foundation interior layer 20a, and similarly layer 200 concentric to core A has a foundation in layer 20b.

Yarn 14 of each layer 20 is wound in a helix. This yarn at all points along the helix coextensive with the core is contacted by longitudinally adjoined helically wound segments of yarn on both sides thereof. These adjoining strands in cooperation with the inner foundation of the layer provide an essentially porous fibrous filter mass for the element.

Contacting the outer periphery of the filter element there is a non-porous filter boundary C. Boundary C is defined with smoke entrance opening 22 adjacent the tobacco 24 and smoke exit opening 26 at the furtherest extremity of tobacco cylinder or cigarette. Openings 22 and 26 are normal to core A, circular in area and have their limits determined and defined by boundary C.

When the tobacco 24 of cigarette cylinder 28 is lit, smoke will travel down the cylinder through entrance opening 22 and out exit opening 26. During its traverse of the filter element, the smoke will strike and contact the individual fibers of the cigarette element. On striking these fibers, the smoke will be deflected along and around the fiber surfaces as spirally wound imparting to the smoke a circumfluous interpenetrating path, deviating the smoke from an otherwise axially parallel path through the filter element. This deflection insures a maximum scrubbing or filtering effect of the trapped and confined smoke interior of the filter element.

The spirally wound fibrous filter of this disclosed invention may be enhanced by impregnation with a viscous liquid. Such a liquid, when coating the surface of the individual fibers interior of the filter element, enhances the filtering effects of the cigarette.

Liquids suitable for impregnating fibrous filters must adhere to the individual fibers in preference to the passing smoke. Further, such liquids must be neutral tasting so as not to impart unnatural or peculiar taste to the tobacco smoke. It is further noted, that when such liquids have the properties of a chemical base they tend to neutralize and absorb the passing tars, nicotines and other compounds having acid properties.

It may further be desirable to provide a mild adhesive which will temporarily bind the fibrous mass of the filter element together as it is wound. When formed with such an adhesive, the filter element of the present invention may then be inserted interiorly of a boundary C without the necessity of winding the boundary to the element.

A specific example of a liquid meeting substantially all of the above requirements may be formed by a solution containing 25% by volume glycerin, 4-8% by volume casein and the remaining portion thereof of fresh whole cows milk. This solution remains interior of the filter while smoke is being drawn therethrough, is essentially neutral tasting, has the chemical properties of a base neutralizing the passing acid impurities of cigarette smoke, and when properly cured forms a mild adhesive adhering the wound fibrous filter element into a solid and unitary, yet porous mass.

A preferred substance for impregnating the helically wound multi-layer filter element of this invention has been found to be non-fat or skimmed cows milk. This milk is standard cows milk with substantially all of the fats removed. By analyses, the resultant material consists of about 90.5% water, 3% to 4% protein, fats, 3%, carbohydrates 5.1% and ash .7%. Primarily, the proteins comprise casein which have an adhesive property and serve to adhere the strands of helically wound roving.

Additionally, it has been found that low-fat milks can be used to impregnate the filter of this invention. These low-fat milks can have a fat content as high as 2.1%.

With reference to FIG. 2, the process of forming the disclosed filter element is specifically illustrated. Core A is shown comprising spirally wound strands of roving 18. These strands turn and advance providing a rotating foundation for sequentially wound layers of yarn 20a, 20b and 200. These layers 20 each comprises parallel lengths of advancing yarn 14 which are wound about the foundation of core A as it rotates and advances. Each length of yarn as helically wound along core A is adjoined longitudinally on both sides thereof by similar lengths of yarn helically wound. Simultaneously with the turning motion of core A and winding of layers 20a, 20b and 20c, an impregnation with a viscous filter liquid takes place through nozzles 30. As is apparent, this impregnation can take place before, during or after the formation of the wound filter. After winding of the filter, the impregnated element passes wringers 32 where excess filter liquid is forceably squeezed from the fibrous mass.

The filter liquid placed on the rayon roving through nozzles 30 can either be poured or sprayed on the advancing roving. Typically, spraying of this filter substance is preferred as it provides only that impregnation necessary to adhere the strands of wound roving and provide the neutralizing and improved filtration effect of the filter liquid.

When impregnated and wound, the filter liquid may be cured so as to adhere adhesively the wound fiberous mass. Such curing is typically provided by passing the wound and impregnated filter element through an oven of approximately 200 F. temperature. By allowing the filter element to remain in the oven for a period of 10 minutes, curing of the filter element into a unitary mass will occur. Temperatures higher than 200 F. can be used but it has been found that these temperatures add an undesired dissome detail by Way of illustration and example for purposes of clarity and understanding, it is understood that certain changes and modifications may be practiced within the spirit of the invention.

coloration to the filter ultimately produced. The wound element when cured is then cut into appropriate lengths, typically of an inch long, for placement in a cigarette.

The filter element of this invention has been specifically described as attached to cigarette. As is apparent, such a filter could be placed interior of a pipe, cigar or other 5 smoking implement to eifect desired filtering and purification of passing tobacco smoke.

Although the foregoing invention has been described in What is claimed is: 1. A filter element for the absorption of compounds contained in tobacco smoke, said filter element comprising:

a core of yarn forming a central longitudinal axis the length of said filter element and terminating at either end thereof;

a first layer of yarn wound in a helix, in contact with said core;

said yarn of said first layer at all points along said helix, co-extensive with said core, in contact with longitudinally adjoining helically wound yarn on both sides thereof;

a second layer of yarn wound in a helix in contact with said first layer of yarn;

said second yarn of said second layer at all points along said helix, co-extensive with said core, in contact with longitudinally adjoining helically wound yarn on both sides thereof, whereby said core, said first layer and said second layer define a porous fibrous filter mass; and

a non-porous boundary in contact with the outer periphery of said fibrous filter mass and defining openings at said ends thereof whereby said smoke flowing through said openings is restricted interior of said filter element to a circumfluously interpenetrating path through the individual fibers of said yarn.

2. The invention of claim 1 and wherein said yarn comprises twisted rayon roving.

3. The invention of claim 1 and wherein said core, and said first and second layers of yarn are impregnated with cows milk.

4. The invention of claim 1 and wherein said core and said first and second layers of yarn are impregnated with non-fat cows milk.

References Cited UNITED STATES PATENTS 6/1962 Parmele 131-266 X 11/1965 Erlich et al. l3l267 X FOREIGN PATENTS MELVIN D. REIN, Primary Examiner US. Cl. X.R. 

